A366610 -id:A366610 - cp's OEIS frontend

A366585 Write down the positive integers. To obtain the terms of the sequence, concatenate groups of these so the first digit of each term is the number of consecutive numbers that are concatenated.

1, 23, 4567, 89101112131415, 16, 17, 18, 19, 2021, 2223, 2425, 2627, 2829, 303132, 333435, 363738, 394041, 42434445, 46474849, 5051525354, 5556575859, 606162636465, 666768697071, 72737475767778, 79808182838485, 8687888990919293, 949596979899100101102, 103, 104, 105, 106, 107

Offset: 1

Tamas Sandor Nagy, Oct 14 2023

Terms beginning with 1 will appear in runs of long linear succession. These are interspersed with clusters of values that tend to increase at other, uneven rates in the sequence.

Cf. A366610, A053067.

lista(nn) = my(list=List(), k=1); while (k < nn, my(s="", n=digits(k)[1]); for (j=1, n, s = concat(s, Str(k+j-1));); listput(list, eval(s)); k += n;); Vec(list); \\ Michel Marcus, Oct 14 2023

from itertools import islice
def A366585_gen(): # generator of terms
    a = 1
    while True:
        c = a+int(str(a)[0])
        yield int(''.join(str(i) for i in range(a,c)))
        a = c
A366585_list = list(islice(A366585_gen(),20)) # Chai Wah Wu, Nov 04 2023

cp's OEIS Frontend

A366585 Write down the positive integers. To obtain the terms of the sequence, concatenate groups of these so the first digit of each term is the number of consecutive numbers that are concatenated.

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